Automatic head for machine tools



H. o. KYLIN 2,641,938

June 16, 1953 AUTOMATIC HEAD FOR MACHINE 'roo s 14 Sheets-Sheet 1 FiledSept. 14, 1948 lium" I \I II I b 1 L IIIIHIII m I INVENTOR.

June 16, 1953 o, KYLlN 2,641,938

AUTOMATIC HEAD FOR MACHINE TOOLS Filed Sept. 14, 1948 14 Sheets-Sheet 2INVENTOR.

June 16, 1953 H. o. KYLIN AUTOMATIC HEAD FOR MACHINE TOOLS 14Sheets-Sheet 3 Filed Sept. 14, 1948 tin N60 INVENTOR. 60.440, 4; BY

H. O. KYLlN AUTOMATIC HEAD FOR MACHINE TOOLS June 16, 1953 14Sheets-Sheet 4 Fild Sept 14, 1948 INVENTOR.

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June 16,- 1953 v H. o. KYLIN AUTOMATIC HEAD FOR MACHINE TOOLS 1315aSept'. 14. 1948 14 Sheets-Sheet 5 IN VEN TOR. a #mwLA June 16, 1953 H.o. KYLIN 2,641,938

AUTOMATIC HEX!) FOR MACHINE TOOLS Filed Sept. 14, 1948 14 Sheets-Sheet 6as 49 48 45 A3 Fig/J IN V EN TOR.

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AUTOMATIC I'EAD FOR MACHINE TOOLS Filed Sept. 14, 1948 14 Sheets-Sheet 768 Mlr 67 61 La (I -64 INVEN TOR.

June 16, 1953 o, KY 2,641,938

' AUTOMATIC HEAD FOR MACHINE TOOLS Filed Sept. 14, 1948 14 Sheets-Sheet9 IN V EN TOR.

June 16, 1953 r o, KYLlN 2,641,938

AUTOMATIC HEAD FQR MACHINE TOOL June 16, 1953 H. o. KYLlN 2,641,938

AUTOM'HC HEAD FOR MACHINE TOOLS Filed Sept. 14. 1948 14 Sheets-Sheet l1Ll L2 IN VEN TOR.

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AUTOMATIC HEAD FOR MACHINE TOOLS Filed Sept. 14, 1948 r 14 Sheets-Sheet12 IINVENTOR. By M 3 June 16, 1953 H, o, KYUN 2,641,938

AUTOMATIC HEAD FOR MACHINE TOOLS ran 5 V' I INVENTOR.- BY M (9/614Patented June 16, 1953 UNITED STATES PATENT OFFICE Henrik 0. Kylin,Cleveland, Ohio, assignor to Bardons and Oliver, Inc., Cleveland; Ohio,a

corporation of Ohio Application September 14, 1948; Serial No. 49,266

7 Claims. (01. 74 472) This invention relates to" machine tools such asturret lathes and more particularly to means associated with the head ofthe machinefor elec-' trically effecting a preselected rate change inthe spindle in either direction of rotation, to gether with means tostop or plug the rate change transmission down to a speed safe forautomatically shifting gears.

It is one of the objects of my invention to provide electricallyresponsive means whereby an operator may, through a central controlsta-' tion, preselect a rate for the work spindle, and, preliminary to arate change, stop or plug the selective gear transmission through whicha plu-' rality of spindle speeds or rates are available, and then impartthe preselected rate to the spindle in either forward or reversedirection of spindle rotation.

Another object of the invention is the provision of a spindle ratepreselecting switch having multiple positions representing the variousspindle rates available in the transmission and having suitableconnection through selected electrical circuits for effecting a ratechange at the will of the operator.

A further object consists in the provision of electrical switch meansresponsive to the action of centrifugal force for effecting aslowing'down' or stoppage of the transmission just prior to a ratechange in the spindle. v

A still further object is the provision of a centralized single controlon the head operable through suitable electrically responsive devices toefiect a preselected rate change in the spindle in either a forward orreverse direction of spindle rotation when said control is moved aboutone axis, and to cause said spindle to stop or slow down to a safe rateprior to effecting a subsequent preselected rate change, when saidcontrol is moved about another axis.

Another object of the invention resides in the provision of means forautomatically locking the gears of a sliding gear transmission inselected meshing engagement while the spindle is running at the desiredrate, but operable automatically to release such of'said gears as arerequired to be shifted in effecting a subsequent rate change.

Another object of the invention is the provision of acentralizedcontrol' for the necessary manual operation of the machine.

Another object of the invention is" the pro vision of two speedelectric" motor as prime mover speed.

, Other objects and advantages of my invention will} becol'ne' moreapparent asthe following description of one embodiment" thereofprogresses, reference being made to the accompanying drawings, in whichlike reference chara ters are employed to designate like partsthroughout the same.

In the drawings:

Figure 1 is a front elevationof a turret lathe embodying my inventionshowing the relative positions of the manualcontrol station and thepresele'ction switch, both on the headstock of the machine;

Figure 2 is a diagrammatic view of a rate change transmission containedin the headstock;

Figure 3 is a top viewof housing above the rate change transmissionchamber of the headstock, with the cover removed and illustrating therelative locations of the main control switch, the rate preselecting'switch, the solenoid shifting units and the centrifugal switch;

Figure 4 a vertical section through the main control switch showing theforward-reverse con- Figure 10 is aside view of the solenoid shiftingunit shown in Figure 9;

Figures 11 and 12, 13 and 14, and 15- and 16 illustrate respectivelyprogressive positions of the solenoid plunger and associated mechanism"for unlocking and shifting a gear cluster of the transmission, Figures11, 13 and 15 being. viewed from one side of" the unit, while Figures12', 14 and 16 are viewed from the opposite side;

Figure 17 is a front view of a preselecting' switch by which the spindlespeeds may be preselected;

Figure 18 is a section taken on line I8l8 of Figure 17;

Figure 19 is a section taken on line I9l9 of Figure 17;

Figure 20 is a development of the selector detent surface;

Figure Zlis a; sideview of a centrifugally operated limit switch devicefor slowing down the transmission preparatory to a rate change;

Figure 22 is a front elevation of the limit switch shown in Figure 21;

Figure 23 is a horizontal section taken on line 23-23 of Figure 21;

Figure 24 illustrates a modified form of preselecting switch forming apart of my invention;

Figure 25 is a plan View taken on line 25-25 of Figure 24;

Figure 26 is a fragmentary view of means for resetting the push buttonswitches shown in Figures 24 and 25;

Figure 2'7 is a wiring diagram illustrating the control circuits for thespindle;

Figure 28 is a wiring diagram showing the circuits for the severalcontrol relays;

Figure 29 is a wiring diagram showing circuit for driving motor;

Figure 30 is a view similar to that of Figure 27 but shows in heavylines the circuits employed preliminary to a rate change in a forwardspindle running direction;

Figure 31 is a view similar to that of Figure 27 showing in heavy linesthe circuits employed in reverse spindle running direction;

Figure 32 is a view similar to that of Figure 2'7 showing in heavy linesthe circuits employed in shifting from one gear ratio to anotherselected ratio; and, v

Figure 33 is a section through one of the solenoids and associated partstaken on lines 3333 of Figure 9.

I have illustrated my invention in the drawings as applied to a turretlathe, although it will be understood the same may be employed withother machine tools having a movable part which is to be driven atselected or preselected rates in either a forward or reverse direction.

In Figure 1 the headstock is shown at I in which is housed a change geartransmission for imparting selected rates to a spindle 2. The driveshaft 3 may be equipped with a pulley 4 for belt drive with a primemover (not shown) such "as a reversible electric motor having twospeeds, or the prime mover may directly drive the shaft 3. In thisfigure I have also shown the general organization and arrangement of themanual control switch 5 by the operation of which the spindle may becaused to rotateat a preselected rate in either direction and by meansof which the rate may be changed by effecting a selected gear ratio inthe transmission. Associated with the forward-reverse shifting controlswitch is a manually operated high-low switch 6 for utilizing either thehigh or the low driving motor rate with any selected spindle rate asindicated by the rate selector switch I. 8 indicates an on-oifswitch'located on the head.

Referring now to Figure 2 I have illustrated in diagrammatic form a ratechange transmission of more or less conventional design in which thedrive shaft 3 is shown as splined carrying a slid ing cluster gear 9 andI0. On the countershaft I l are keyed the gears I2, I3, I4 and I5, thegear I2 being engageable with the gear 9 when the cluster is in theposition shown, and the gear I being engageable with the gear I3 whenthe cluster is shifted to its other extreme position on the shaft 3.

A splined shaft I6 slidably carries the gear clusters I'II8 and I9-20for meshing engagement respectively with the gears I4 and I and thegears 2l22 keyed to the spindle 2 depend- 4 ing upon the positions ofthe sliding clusters as will readily appear from the figure.

Each of the three sliding gear clusters is operated on its splined shaftby a fork and lever illustrated at 23 in Figure 10 and at 23, 24 and 25in Figure 3. Three fork and lever units are keyed to shafts 26, 21 and28 respectively of the electrically responsive shifting units 29, 30 and3|. Each of the shifting units comprises a pair of solenoids mountedside by side as at 32 and 33, each solenoid having a plunger 34 axiallymovable therein and pivotally connected at 35 through linge 35 and 36 tothe outer end of a cross bar 31. Each cross bar of each unit is keyed tothe respective shafts 25, 21 and 28, as at 38, to rock the shaft whenthe respective cross bar is rocked and to thus move the fork and leverunit to slide the gear cluster which it controls.

It will be noted that when solenoid 32 is energized, its plunger 34 willbe drawn axially into the coil, as in Figure 9, rocking the cross bar 3!to the position shown to withdraw the plunger 34 of the deenergizedsolenoid 33. This action is, of course, reversed when solenoid 33 aloneis energized. In this connection I have provided simple means forlocking the position of the rockable cross bar 3'! and consequently theshaft to which it is keyed and the gear cluster controlled by saidshaft, that is, locking the selected gears in mesh.

In Figures 3, 9 to 16 inclusive and Figure 30, I have illustrated oneform of gear locking means which may be employed.

Referring first to Figure 3 wherein are illustrated the several solenoidoperated shifting units and Figure 9 illustrating one of these units inmore detail, the gear locking mechanism includes the link 36 pivotallyconnected at one end to the solenoid plunger as at 35 and which isprovided with an elongated slot 4|] near its outer end and runningsubstantially longitudinally of the link. The link 36 is notched alongits outer side as at 4|, the notch having a beveled surface along itstop side as at 42 to receive a portion 43 of a spring urged latch bar 46normally urged toward the slot by means of the spring 44. Thisportion ofthe latch bar is also provided with a beveled surface 45 which isadapted to engage and ride along the beveled surface 42 of the notch ofthe link. The latch bar 46 is provided with a recessed portion 41through which the link 36 is adapted to pass vertically, the 0ppositeend of the latch bar 46 being formed with an off-set latch portion orstop 48 which is adapted to be projected into the path of the hub 49keyed to the shaft 26 when the portion 43 of the latch bar is projectedinto the notch M of the link 36. This is more clearly shown in Figure12, and when the portion 48 of the latch bar is in locking engagementwith the notched portion 50 of the hub 49, the hub and consequently theshaft 26 will be locked against rotation in one direction or, in aclockwise direction in Figure 12, thus preventing disengagement of themeshed gear clusters controlled by the shifting unit carried on theshaft 26.

In order that longitudinal movement of the link 36 occasioned byenergization of one of the solenoids 32 or 33 in the unit illustrated inFigure 9 may be translated to rock the bar 31 keyed to the shaft 26, thebar 3! carries at opposite ends a pin 52 positioned within the elongatedopening 40 of the link 36 so that when the solenoid 33 in Figure 9 isenergized to draw the aesigosa i corresponding plunger 34 downwardly,the linlc 36 will. move downwardly'until the upper end of. the elongatedslot-1 engages the pin 52.. Con.- tinued downward movement of" thelinli. 36 will engage the pin withthe top of: the slot and cause the bar31 to. be rocked ina clockwise direction with the shaft 26 asillustrated in Figure but it. is to be noted that during the movementof: the link 36 as represented inFigures'. 11 .and'. 13 when the slottedportionof the link moves. from the positionshown in Figure: 111 to thatshown in Figure 13, there is no movement of the rocking bar'31 Duringthis portion ofthemovementof the plunger 34, the link 36whichi is alsopivotally' carried at'35- to the plunger will also move downwardly, theinclined surface 42 of the link notch 41' willengageand there will. berelative sliding movement between it and thebeveled surface 45 of thelatch bar to move the l'atch bar to the right against the compressionof. the spring- 44 as indicated in Figures 12 and 14. This movement of.the latch bar will, of course, disengage the offset. portion 48 from thenotched portion. 50 of the. hub 49, andcontinued movement of." the links36. and 36 downwardly will be translated to unlock and rock. the bar 31and the shaft 26.

As this function occurs, the pin 52 carried by the opposite end of therocking bar 3'l-will engage the upper end of the elongated slot 40formed in the link 36 actuated by the plunger of solenoid 32 and arocking movement of the rock bar 31 as described above in a clockwisedirection in Figure!) will cause the plunger of the deenergized solenoid32 to be lifted by the link 36 the link 36 thereof passing through therelieved portion 41 of the latch bar 46 The notched portion 4| 1 or thelink 36 then comes opposite the portion 43 of the latch bar-46 whereuponthe compression of the spring 44 will thrust the portion 43 intoengagement with. the notch 4P. In the meantime the rocking movement. ofthe bar 31 in a clockwise direction will. bring the notched portion 56of the hub' 49 into position to be engaged by the stop 18 on the innerend of the latch bar 46. thereby'l'ockingii the position ofthe shaft. 26and of the shifting lever carried thereby against rotative movement in acounter-clockwise direction. U'pward' movement. of the link 36 ofsolenoid 32' to its extreme upper position will. cause the pin 52. to beengaged with the lower end of the elongated slot 4.

The operation of. the several solenoid operated shifting units. issubstantially the same, and I have described only'the operation of oneunit, it being understood that in: further disclosing this inventionwhen reference is made to the sequence of operation. of the variousparts of the unit, such reference will. serve to define its function inaccordance with the above-description'.

In Figures 11 through 16, Figures 11 and 12 illustrate the relativepositions'of the mechanism including the gear shifting lever 23. whenthe latter is locked in one position". to maintain. a gear cluster inmesh with its associated gears in the transmission. In Figures 13 and14' thesame parts are illustrated, thepositionofthe shifting lever 23remaining unchanged. In these figures the initial downward movement ofthe links 36 and 3B for substantially a distance equal to the length ofthe elongated slot 40 is shown as representing the unlatching movementof the plunger and. link 36 wherein the portion 43' of the latchbar 46isiurged-out of the notched. portion of. the. link 36 against thecompression of theisprin'g 44, thus unlatchingthe barv from the hub 49.

Figures 15 and 16 illustrate the remaining link with the pin 52 carriedby the rocking bar 31 to rock this bar toa position shown in Figure 15,it being understood that during this latter movement of the plunger andlinks 36 and 36 the. links 36 and 36 of the solenoid 32 are movedupwardly with its plunger until the portion 43 of the latch bar 46engages the notch M of link 36 and the latch 48 engages the notchedportion 50 of. the hub 49 to thereby lock the gear shifting lever 23 inthe position shown in Figure 15.

In Figures 3, and 17 to 20 inclusive I have illustrated one form ofpreselector switch by which. any one of a plurality of available spindlerates may be selected, while in Figures 24, 25 and 26 another form ofselector means by which any available rate may be selected and employedis shown.

Referring presently to Figures 3 and 17 to 20 inclusive, the selector orpreselector switch is mounted on the headstock of the machine andincludes a housing I in which a plurality of limit switches HL, AB, CDand Eli are carried and extend radially inwardly of the casing so thattheir respective plungers may project into engagement with the detentedsurface of the selector drum In Figure 20 I have shown a development ofthe drum 60 illustrating the arrangement and spacing of the detents inthe drum surface. It Will be noted in this figure that there are fourcircumferential series of detents, the detents in each series beingarranged with respect to one another and with respect to certain detentsof the other circumferential series as to receive. the plungers of therespective limit switches above referred to in a selected patterndepending upon the rotative position of the drum in the casing 1.

It will be noted that one circumferential series of detents" indicatedat 6| corresponds to and lies in the path. of the plunger of limitswitch AB, while the series of detents 62 are arranged to lie in the.path of the plunger of the limit switch EF. Likewise the respectiveseries of detents 63 and 64 lie in the path of the respective plungersof. the limit switches CD or I-IL.

The drum 69 carries a dial 65 rotatable therewith and a forwardlyprojecting knob portion 66 for rotating the dial and the drum 6!]. Theouter face'of the dial is graduated in a manner somewhat similar to thatshown in Figure 1'7 illustrating the various positions of the dial anddrum in thecasing available for selecting or preselecting a desiredspindle rate. On the inner face of the dial 65 there is provided acircumferential series of detents fil engageable by a spring pressedball 68 mounted in the casing 1' so that the selected rate may beaccurately obtained by lining up the desired rate as indicated on thedial with the pointer 69 marked on the casing.

It will benoted from an examination of Figures' l8 and 19- that theseveral limit switches HL, AB, CD and EF are positioned in the casing sothat the plu-ngers will operate through openings 10- positionedatselected points in a direction axially of the drum 60 so that theplunger will operate in a radial direction with respect to the drum toengage the respective series of detents GI, 62, 63 and 64.

In Figures 24, 25 and 26 I have illustrated a modified form ofpreselector or selector switch which may be used in place of that formalready described. In this form of switch it will be noted that I haveemployed a plurality of push buttons arranged in a circumferentialseries on a face plate II which is carried by a base I2 bolted to theheadstock of the machine, the push buttons being indicated generally atI3, each of which when depressed engaging its terminal inner end 14 withspring contacts I carried on an insulating support I6. The shafts ll ofthe respective push buttons operate axially through a disc I8 and eachis provided with a cam and stop I9 formed on the member 80 which in turnoperates through an opening or slot BI in a looking disc 82 rotatable ona shaft 83. The fixed disc I8 is provided with a stud 84 in which oneend of a tension spring 85 is anchored, the other end of the spring 85being fixed in a stud 86 carried by the rotatable disc 82, to normallyurge the disc 82 to move in a clockwise direction in Figures 24 and 25,by allowing the disc to move in a counterclockwise direction when one ofthe switch push buttons is depressed as indicated by the right handbutton I3 in Figure 25. Such movement of the disc 82, is caused bysliding engagement of the inclined surface 81 of the cam stop with theside wall 88 defining the opening 8| as the button is depressed.However, when the button and switch shaft 11 reach their inner limit oftravel, the cam stop will have assumed the position shown in Figure 25,that is, beyond the disc 82 and beyond the opening 8|, whereupon thetension spring 85 will rotate the disc 82 in a clockwise direction tolock the depressed button in that position and consequently close thecircuit through the respective spring contacts I5 engaged or bridged bythe conductor end I4 of the push button.

It will be seen that a depressed push button may be released only bydepressing another selected push button switch in the series. Whenneither push button is depressed, the disc 82 will be rotated in acounterclockwise direction as described above to bring the openings 8Iinto alignment with the cam stop 19 and to permit the previously lockeddepressed button to be released and reset by the compression of itsre-setting spring 89.

Referring now more particularly to Figures 3 to 8 inclusive, I haveshown a control station comprising two levers, one movable selectivelyto positions foreffective rotation of the spindle at selected rateseither in a forward or reverse direction, to plug or brake the primemover, driving the spindle preparatory to changing the spindle rate, andto shift from one selected rate to another throughout a range of ratesavailable through the transmission, the other lever being movable toselect either the available high or low speed of a multiple speeddriving motor having driving connection with the shaft 3 through apulley 4 and a belt (not shown).

This control is located on the headstock as indicated at 5 and 6 inFigure 1, preferably adjacent the preselector switch I, and includes abody 90 having an axial opening 9I within which the sleeve I06 and shaft93 are rotatably mounted in coaxial relationship to permit movement ofthe respective control levers 5 and 6 about a vertical axis in eitherdirection. The lever 5 which controls the actuation of the forward,reverse, braking and shifting limit switches, LSF, LS--R, LS-B, and LS-Srespectively is also capable of movement about a horizontal axis locatedin the pin 94 when the lever 5 is in the shifting position to actuatethe limit switch LS-S. The lever 5 is normally urged to its horizontalposition as shown in full lines in Figure 4 by means of the springpressed plunger 95 carried by the lever and engaging the bearing surface96. are provided on the base and project in the path of movement of thelever 5 about its vertical axis to limit such movement between saidpins.

With particular reference to Figure 6 it will be noted that I haveprovided a cam 99 keyed to the shaft 93 and rotatable with the shaft inthe axial opening 9| of the body 90. This cam is provided with two flatsI00 and IOI and with a nose I02 therebetween. When the lever 6 is inneutral position as at N in Figure 3, the parts will be in theirrelative positions as shown in Figure 6. The plungers of the limitswitches LSL and LSH project radially through the body 90 and normallyinto the respective spaces between the flats I00 and IM and the innerwall of the opening 9i as shown in this figure. Diametrically oppositethe nose I02 there is provided a 'V recess I03 openingoutwardly toreceive the end of a leaf spring I 04 anchored in the body by means of abolt I05. By this means the cam 99 is normally urged to the positionshown in Figure 6, but when the lever 6 and the shaft 93 are moved forinstance to the left in Figure 3, the cam 99 will rotate in a clockwisedirection, flexing the spring I04 and bring the nose I02 of the camopposite the plunger of the limit switch LSH, thereby depressing theplunger and operating the switch as will be described in detailhereinafter. Likewise an opposite movement of the lever to the right inFigure 3 will cause the cam to rotate in a counter-clockwise directionto depress the plunger of the limit switch LS-L.

Keyed to rotate with the sleeve I05, movable with a shifting of thelever 5, is a cam I0'I having a plurality of noses I08, I09 and H0which, depending upon the rotative position of the cam, are adapted toengage and depress the plungers of the limit switches LS-R, LSB andLS--F respectively, the peripheral portions of the cam between theserespective noses being relieved so as to provide clearance for thenormally projecting plungers of these limit switches. The normalposition of the cam I0! is illustrated in Figure 8, there being a leafspring III secured in the body 90 by means of a bolt II2, which projectsinto a recessed portion of the cam indicated at II3 to be engaged by oneor the other of the side walls of this recessed portion, depending uponthe direction of rotation of the cam when operating the lever 5.

The lever 5 carries a stud I I4 projecting below its under surface forengagement with the normally projecting plunger II5 of the limit switch'LS-S when the lever is moved to gear shifting position and the stud I I4is in substantial alignment with the plunger I I5. When the parts are inthis position and the lever is depressed as indicated by the brokenlines in Figure 4, the stud will engage the plunger II5 to depress itand thus operate the limit switch LSS.

-In Figure 6 I have provided a stop pin II6 Suitable stop pins 91 and98.

ing short of the top of the hollow shaft I20 to projecting upwardlyfrom-thebase of-the control into a radial opening II'I formed in thebottom I a spring pressed ball I30 urged upwardly by the spring I'3I forengagement with anyone of the detents I32 to indicate to the operatorwhen the lever is in the selected properposition. The-three detents I32correspond to the three aforesaid positions of the lever-5, thedetent tothe left in Figure 7 representing the reverse position of the lever, theintermediate detent representing the brake position of the'lever, whilethe detent on theright corresponds to the forwardfposition of the lever.

I have also provided means to stop or slow down or plug the transmissionto a pre-determined speed for safely and automatically shifting gears.According to this invention I have provided such means-which iscentrifugally responsive in the operation. More specifically, referringto Figures21, 22 and 23, the driven shaft II of the transmission carriesa gear I It in mesh with a gear II9 for driving the shaft I29 of thecentrifugallyresponsive device IZI. This device includes a pair offingers I22 pivotally connected at I23 to the shaft I20 and rotatabletherewith. Within the'hollow shaft I26 there is provided a rod I26extending axially thereof and terminataccommodate 'therein a ballbearing I25. At increased .ratesof rotation of the shafts II and 120centrifugal force will cause the fingers I22 to move outwardly of theshaft I28, and to thus raise the rod 12s in the hollow shaft to rock theeral functions-and purposes of the invention. In

the interest of clarity I have shown in Figure 27 the wiring diagramwith the various electric units thereof in their normal position whilethe machine is at rest, while in Figures 30, 31' and 32 the same diagramis illustrated but those portions of the circuits which are affectedunder certain conditions of operation are shown in heavy lines in rthesaid several views, 1. 'e., in

Figure-'30 the diagram is lined heavily for those circuits employed whenthe spindle is running in forward direction, and in Figure 31 the heavylined portion thereof illustrates'those portions of the circuit employedjust "after the braking sequence is initiated by-depressing the lever 5to actuate the limit switch LSB, while Figure 32 is heavily lined toindicate those portions of the circuit in use just after the shiftingsequence is initiated by energizing .the limit switch LS-S. In thisinstance it will be noted that when the speed of the transmissionreaches a pre-determined value, centrifugal switch CS-I will close thecircuit through LL-Z to L-2. This will effect a shifting of the gears inthe transmission according to the circuits determined by LS-AB, LS-CD,LSEF and LSHL.

More specifically the operation of the invention may be described asfollows:

Assuming that the spindle is at rest, the var-ious electric controlswill be as indicated in Figure 27. When it is desired to operate thespindle, say in a forward direction at a preselected or selected rate,the operator selects such rate by turning the selector dialIiiluntil'the selected rate indicated on the dial is opposite the mark G9 onthe casing 7 and, being ready to set the spindle into motion, hedepresses the on button of the lever I26 carried by the support I21 forthe limit switch CS-I. The lever I26 is pivoted to the base I21 at I28and has an arm I29 extending upwardly as shown in Figure 21.

,This arm "I29 carries the adjustable bolts I33 and I34 arranged side byside and in alignment with the p-lungers I35 of the limit switches CS-Iand 08-12 respectively, there being an adjustable bolt I36 carried inthe upper end of the arm I29 for engagement with the spring pressedplunger I31 carried in the support I38. The plunger I3! is normallyurged outwardly in engagement with the inner end of the bolt I36 to inturn normally urge the lever I23 downwardly against the ball I25 and therod 12 3; however, when the rate of rotation of the hollow shaft I20 isincreased and the fingers I22 are forced outwardly by centrifugal force,the rod i2 3 will move upwardly in the shaft to raise the lever I23 andto move the arm "I29 to the right in Figure 21 against the compressionof the spring pressed plunger I37 to actuate the respective plungers I35of the centrifugal switches CS-I and -CS-2.

The centrifugal switches CS-I and 08-2 are closed as indicated in thewiring diagram of Figures 30, 31 and 32 due to the actuation of thecentrifugal device under operating rates but are a normally open whenthe spindle is not'moving as in Figure 27. The operation of this unitwill be described in conjunction with the description on-off switch 8;

Since the off"buttonwill bridge the contacts I50 when th e"on button isdepressed, it will be seen that current will flow from L 2 through therelay LVR to L-I. When this relay is energized, the normally open relayswitch LVR will be closed as indicated in'Figure 30 maintaining a flowof current from L-I to L-2 through LVR as wel1 as to the remainder ofthe wiring circuit therebelow.

While the on button is depressed, current ilows'through control relayCRI-I or control relay CR-L depending upon the position of the selectordial 60 and the rate selected. If the rate selected is one requiring thedriving motor to operate at its high speed rate, then the control relayCR-H will be energized, and conversely CRL will be energized where therate selected is one'obtained throughthe low speed of the driving motor,Assuming that the selected rate is one obtained through the high speedof the driving motor'and that CRH is energized, the limit switch LS-HLwill be actuated to close the circuit from ILL- 2 through control relayCR,H, in the present example. Simultaneously control relay CR-Ii isenergized to actuate the motor contactor-H (Figure 29) The driving motoris now set to run at its high-speed level.

When it is desired to set the spindle in for- Ward motion at theselected rate, the operator moves the'lever 5 to :the extreme left as inFigure .3 to its forward station. In so doing the point I IIl of the camI05 engages the plunger of the limit switch LS-F and depresses the samecausing 'current to flow through control relay CR-I to close thenormally open contacts of CR-I allowing current to flow therethrough andthrough the normally closed contacts CR-Z bridging the limitswitoh LS-F.Control relay CR-l remains energized after limit switch LSF is opened orthe forward-reverse lever is in the first detent position as describedhereinbefore.

When the contact of control relay CR-l is closed, the control relayCR--F is energized.

When the forward-reverse lever 5 is moved to the forward position asindicated in broken lines in Figure 3, the normally open limit switchLSF will be closed energizing the control relay CR-l and closing allnormally open contacts 03-] as illustrated in Figures 27 and 30. Thecontrol'relay CR-I remains energized after the limit switch LSF isopened or while the forward-reverse lever is in the detent position tothe left in Figure '7. At the same time it will be noted that thecontrol relay CRF which is normally deenergized is energized when thecontact of CR-l is closed. Under these conditions the motor contactors Fin Figure 29 will be actuated to supply current to the motor, to drivethe motor in forward rotation.

With the motor and the transmission running the centrifugally responsivedevice illustrated in Figures 21, 22 and 23 will operate to closecentrifugal switches CS-l and CS-2 as shown in Figure 30.

The control lever 5 then may be moved to the intermediate detentposition as shown in Figure 7 which corresponds to the ineutral orbraking position, and in such position the limit switch LSB will beactuated to close the circuit from L-2 to L-l energizing the controlrelay CR--B, opening the circuit through control relay CR-F and causingthe forward motor contactors to open as illustrated in Figure 31. Duringthis position of the lever 5 the control relay CRR is energized throughcontact with CR-l, CR-B, centrifugal switch CS-2 and contact CR-4, thelatter of which refers to motor contactor R (Figure 31) and causes themotor to dynamically plug toward a reversed rotation, thereby effectinga braking action in the motor to reduce its forward speed to apredetermined low rate of rotation determined by the setting of thecentrifugal device shown in Figure 21 whereby the centrifugal switchCS-Z actuated by the said device will be opened.

Opening of the circuit through CS-2 will energize control relay CR-3through contact CR4 as shown in Figure 27.

Control relay CR-4 in turn closes through contacts CR-3 and CRr-B-Control relay (JR-4 then opens up the normally closed contacts at linesfrom CR4. The circuit established through con trol relay CRR as inFigure 31 is in turn opened, opening the contactors R (Figure 29), thusstopping the motor. Any further rotation of the transmission by externalmeans other than the motor, sufficient to cause the centrifugal switchCS-Z to become depressed, will not permit the relay CRR to c"lose.

The speed of the motor may be changed as explained above by shifting thelever 6 from one position to the other. If the lever is moved to theright in Figure 3 or to low speed position, the

limit switch LSL will be closed, energizing the control relay CRL andsubsequent control relay CR-! and the motor contactors L (Figure 29). Bysuch means either the high or the low speed of the motor may be madeavailable in either its forward or reverse direction of rotation.

With the forward-reverse lever 5 in shifting position a preselectedspindle rate as determined by the setting of the preselector switch maybe obtained by depressing the lever 5 to close the limit switch LSS.Referring to Figure 32 closing of the limit switch LS-S by briefdepression of the lever 5 will energize the control relay CRS whichremains energized through the contacts CR-S and TDR (time delay relay).The circuit through CR-F is broken and control relay CR-R is energizedthrough control relay CR-l, switch CS-l and contact CRS. When the rateof rotation of the spindle drops below a predetermined critical pointcentrifugal switch CS-I moves to its normal position as shown in Figure27. Line LL-2 is then connected through to L-2 energizing control relaysCRAB, CR-CD, CREF, CR--H, CRL, depending upon the positions of the limitswitches LSAB, LSCD, LSEF, LSHL as determined by the preselector switch.Thus in turn the gear shift solenoids A or B, C or D, E or F and CR-6 orCR-! and subsequently H or L will be energized.

When the control relay CRS is energized, the time delay relay TDR isalso energized through closing the contacts CRFS thus holding thiscircuit closed for a predetermined time interval, whereupon the normallyclosed contact TD-R is opened, deenergizing control relay CRr-S, thusrestoring the contacts to their respective positions at the start andagain en ergizing the motor to run in a forward direction.

In Figure 28 is illustrated an electrical wiring diagram forming acounterpart of that shown in Figure 27, when the type of preselectorswitch shown in Figures 24 and 25 is employed. As described above thistype of selector or preselector is operated by means of push buttonswitches and a latching mechanism.

In Figure 28 the respective selector push button switches are connectedto control relays and switches CR,ACEL through CRBDFH, while the controlrelays and switches CRr-H and CR-L of Figure 27 are replaced by CR-H andCR-L in the present figure. The shift solenoids A, B, C, D, E and F,Figure 27, are shown by the same designation in Figure 28 and areoperated in the manner illustrated. In the operation of the selectorswitch shown in Figures 24 and 25 with the circuit shown in Figure 28 asa spindle rate is selected, for instance, a rate corresponding to thecontrol relay CR-ACEL, the corresponding push button is depressed andlatched. With the drive runrung forward, the shift cycle is started bymovmg the control lever 5 to the shift position and by depressing it inthis position. The driving motor is thus plugged to a slow predeterminedspeed and line LL-Z is thereby connected to line L-2. Control relayCRACEL is energized closing contacts, energizing solenoids A, C, E, andCR-L. After a predetermined time delay, the driving motor starts up inthe same manner as described hereinbefore and of course subsequently tothe selected gear ratios established through the transmission. The sameoperation occurs when any other of the available rates is selected andthe corresponding push button on the preselector depressed and latched,the efiective circuits being established through the proper controlrelays and switches dependmg upon the rate selected and thecorresponding push button depressed. This is clearly illustrated inFigure 28.

I claim:

1. In a machine tool, an electric driving motor, a spindle, selectivegear transmission means for rotating said spindle in forward or reversedi-

